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authorSimon Derr <simon.derr@bull.net>2012-09-17 15:16:30 +0200
committerEric Van Hensbergen <ericvh@gmail.com>2012-09-17 14:54:11 -0500
commit584a8c13d58423462680907d4cc40d9929c9030a (patch)
tree17191b8555e06f8f62aaea1c5a76fde040980e00
parent1957b3a86f8eb5ceab32e3aae99e2822258aa530 (diff)
9P: Fix race in p9_write_work()
See previous commit about p9_read_work() for details. This fixes a similar race between p9_write_work() and p9_poll_mux() Signed-off-by: Simon Derr <simon.derr@bull.net> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
-rw-r--r--net/9p/trans_fd.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 7088a94b260..b2c308fffb8 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -476,10 +476,9 @@ static void p9_write_work(struct work_struct *work)
clear_bit(Wpending, &m->wsched);
err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos);
p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err);
- if (err == -EAGAIN) {
- clear_bit(Wworksched, &m->wsched);
- return;
- }
+ if (err == -EAGAIN)
+ goto end_clear;
+
if (err < 0)
goto error;
@@ -492,19 +491,21 @@ static void p9_write_work(struct work_struct *work)
if (m->wpos == m->wsize)
m->wpos = m->wsize = 0;
+end_clear:
+ clear_bit(Wworksched, &m->wsched);
+
if (m->wsize || !list_empty(&m->unsent_req_list)) {
if (test_and_clear_bit(Wpending, &m->wsched))
n = POLLOUT;
else
n = p9_fd_poll(m->client, NULL);
- if (n & POLLOUT) {
+ if ((n & POLLOUT) &&
+ !test_and_set_bit(Wworksched, &m->wsched)) {
p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
schedule_work(&m->wq);
- } else
- clear_bit(Wworksched, &m->wsched);
- } else
- clear_bit(Wworksched, &m->wsched);
+ }
+ }
return;